Noise emission represents a significant design criterion, particularly for medical scanners. An important noise source on operating a scanner is the anti-friction bearing which continually generates structure-borne noise by a permanent rotation (rolling contact) of the rolling bodies and transfers it to the connected structures which emit it as air-borne noise.
To reduce noise emissions, anti-friction bearings are known in which for example the rotor wires are embedded into a non-metallic vulcanized intermediate layer (see DE 10 2005 000 754 B3) or in which the rotor rings are disposed in liner rings made of elastomer (see DE 103 31 150 B4) or in which an attenuating material not essentially increasing the built size is disposed at least between a rotor wire and a bearing ring in an enhanced rotor wire bed of the bearing ring (see EP 71 026 A1).
With the afore-mentioned bearings, structure-borne noise from the rolling contact is attenuated by additional joints and plastic elements. With high peripheral speeds, however, those measures described herein above are frequently insufficient to keep the noise level of the bearing at an adequately low level.